The rivalry between the Boston Red Sox and New York Yankees is reaching peak intensity this season. A lot of that is because the storied franchises are once again battling over the top spot in the AL East standings. But there’s been bad blood on the field fueling the feud too. That includes one run-in that turned physical in April.

The latest disagreement took place during Boston’s 4-1 win against the Yankees Friday night at Fenway Park. And this time, the series of events left Boston’s rookie manager Alex Cora steaming mad.

What set Alex Cora off?

Mookie Betts, the Red Sox MVP candidate, nearly wore a 96-mph fastball. That’s enough to anger any manager, regardless of the circumstances. But there were other factors too that pushed really pushed Cora’s anger over the edge.

It started with Red Sox starter Rick Porcello hitting Yankees leadoff batter Brett Gardner with an 0-2 pitch to begin Friday’s game. In the bottom of the first inning, New York’s Luis Severino buzzed Betts with a first-pitch fastball under his chin. The Yankees ace has undeniably had his share of command issues recently. However, Cora and the Red Sox were convinced the pitch was in retaliation for Gardner being plunked.

Regardless of intent, the pitch in question was dangerous. Considering the bad blood that previously existed, home plate umpire Adam Hamari issued a warning to both dugouts in an attempt to prevent further retaliation.

If Cora wasn’t mad enough before, this really set him off.

Boston Red Sox manager Alex Cora gives an earful to home plate umpire Adam Hamari after the Red Sox and Yankees were warned during an intense first inning. (AP)

The Red Sox manager charged at Hamari and was ejected for the first time in his managerial career after a profanity-laced tirade, some of which made it through on television. Cora was adamant then, and again after the game, that Porcello’s pitch was not intentional. In his belief, the umpires overreacted by issuing warnings, when in his opinion only one team acted intentionally.

Cora: "They know how I feel about it. I don’t appreciate them throwing at Mookie Betts’ head. If they felt 0-2, front-door sinker had intent, well, first pitch of the game, right at the head of the best player in baseball – there’s intent."

Major League Baseball will ultimately make the final determination on intent. If they believe Severino’s pitch was in retaliation, he could face a fine or suspension.

While Friday’s game was completed without further incident, this situation is clearly still simmering. Cora offered this final take Friday, which clearly doubled as a jab at Severino.

Alex Cora was asked if after Severino-Betts, the situation was over. He gave this walk-off response, getting up to leave as he finished it (the question had been announced as the last): “I don’t know, we scored four runs in less than six innings. Is that a quality start?"

What led to the Red Sox-Yankees brawl in April?

The tension began when Boston shortstop Brock Holt took exception to then Yankees’ first baseman Tyler Austin making an aggressive slide on a force play at second base. Austin had his left foot elevated as he slid into second base, which caused him to spike the back of Holt’s leg.

Austin insisted his slide was clean after the game. The Red Sox felt then like they feel now about Severino’s pitch. Cooler heads prevailed initially, but it boiled over innings later when reliever Joe Kelly drilled Austin with a fastball. That led to a benches-clearing brawl with Kelly firing off a series of punches.

Kelly was suspended six games for his actions. Austin saw his five-game suspension reduced to four games on appeal.

Will the bad blood continue?

We don’t anticipate things getting April-level heated again. Both teams have too much to lose in that scenario as the postseason nears. After Friday’s win, Boston owns a 7 1/2 game lead in the AL East standings, while New York is up five games in the AL Wild Card standings. Both are obviously in great position to play beyond the regular season.

Of course, they also play each other eight more times, including Saturday and Sunday. That’s a lot of opportunity for more bad blood to brew.